43 6 Lakes. 



in the work. If we have an inclined plane with a 

 long slope, gentle or steep, water will run upon it 

 because of the slope ; and, aided by atmospheric dis- 

 integration, it will cut out a channel, but it cannot 

 make a large rock-bound lake-basin, though it can 

 scoop out a small one below a waterfall, or where two 

 rapid streams meet, it may hollow out a pool or linn 

 by reason of the turbulence of the water. 



Again, it has been contended that the hollows were 

 formed by the disturbance of the rocks, so as to throw 

 them into a basin-shaped form. But when we take 

 such lakes as those of Geneva, the lake of Thun, the 

 lakes of Lucerne, Zurich, Constance, and the great 

 lakes on the Italian side of the Alps, or many of the 

 Welsh, Cumberland, or Highland lakes, and examine 

 the strata critically, we find that they do not lie in the 

 form of basin-shaped, synclinal hollows, but, on the 

 contrary, the strike of the strata often runs right across 

 the lake-basins instead of circling round them, or they 

 may be bent and contorted in a hundred curves all 

 along and under the length of the lake. Such syn- 

 clinal depressions are the rarest things in nature : that 

 is to say, hollows formed of strata bent upwards at 

 the edges all round into the form of a great dish, the 

 very uppermost bed or beds of which shall be con- 

 tinuous and unbroken underneath the water of the 

 lake. Some such synclinal hollows are found in the 

 upper valleys of the Jura, but without lakes, and in 

 which the drainage runs into potholes, and finds its 

 way to the level of the Val de Travers, where ready- 

 made rivers issue from caverns in the Secondary rocks. 

 But these synclinal hollows can be explained on prin- 

 ciples quite different from those I have to propound. 

 If such synclinal lake-basins exist at all, I never saw 



